The present invention relates generally to ink curing apparatus and methods, and relates more particularly to a method and apparatus for transporting articles past one or more sources of radiation within an enclosure.
Various articles have labels or designs printed upon their exterior surfaces with ink which may be cured by exposure to infrared or ultraviolet radiation. Typical of such articles are plastic containers or bottles having necks, and larger containers such as buckets. Because the printed matter on such articles frequently extends around the entire circumference of the article or is located at various locations about the circumference of the article, it is desirable that curing apparatus provide 360.degree. exposure to ultraviolet radiation for each article. In the past, some types of curing apparatus have included means for gripping container necks to support them and rotate them while transporting them past an ultraviolet lamp. While such apparatus may be satisfactory for use with necked containers, it may not be suitable for curing ink on large articles such as buckets which do not have necks.
Large articles such as five gallon paint buckets or even larger barrels are difficult to handle on automated or semi-automated equipment. Most existing equipment is not, or cannot be, adapted to cure such articles in an economical manner. There is a need for an inexpensive and efficient apparatus to cure ink on such large articles.
Exposure of persons to excessive amounts of ultraviolet radiation is undesirable. Accordingly, ultraviolet curing apparatus may include an ultraviolet lamp enclosed within a housing for confining the radiation, and means to transport articles past the lamp within the housing so to expose the articles to the ultraviolet radiation without exposing any workers to the radiation.
In commercial printing operations, ultraviolet curing apparatus is commonly used in proximity to the printing equipment which deposits the ink on the articles so that the ink may be cured immediately after it is applied. It is desirable that the curing apparatus be capable of being loaded and unloaded with the printed articles in a safe and expeditious manner and that the apparatus be capable of curing articles at a rate equal to the output rate of the printing apparatus. The exposure time required to cure the ink on a particular article may be relatively short, and accordingly the time required for loading an article and transporting the article from an input location to the curing station and then to an output location for unloading the article with cured ink thereon may be significant. There is a continuing demand for ultraviolet curing methods providing improvements in the handling of articles to increase the efficiency of curing operations.